Since 1887, when the American Journal of Obstetrics noted that a pregnant woman gored by a bull was likelier to survive than one who had a Cesarean section, surgical childbirth has gone from an act of desperation to the most common major surgery in the U.S. Yet compared with vaginal deliveries, Cesareans have a higher risk of complications, and a higher price—unnecessary C-sections cost insurers an estimated $5 billion a year. And that doesn’t factor in an even greater expense: new research finds C-section babies to be more prone to various long-term health problems.